The work done by the external force on a system equals the change in _________ energy.

Explanation

1. Since total mechanical energy (KE+PE) of a system is conserved when no external force acts.
2. Therefore External forces will either change KE or PE or both of a system.
3. Hence, work done by external force will change total energy.

Therefore, The work done by the external force on a system equals the change in total energy.